The invention relates to a sensor apparatus, a system and a method for protecting an occupant, in particular a driver, of a vehicle from being blinded or dazzled by light sources situated outside of the vehicle. The invention also relates to a motor vehicle having such an apparatus.
The driver of a motor vehicle being blinded or dazzled by external light sources, such as e.g. direct sunlight, sunlight reflections or headlamp lights from other vehicles, may constitute a significant traffic endangerment, particularly if the driver can no longer correctly detect the traffic situation on account of the glare.
DE 198 24 084 A1 has disclosed a glare protection device for a motor vehicle, in which individual matrix elements of a filter disk, embodied in a matrix-like manner, may be darkened such that a darkened region may be produced on the filter disk. The darkened region follows the movement of a glary object and adapts to the glary object in terms of the size and darkening behavior thereof. The glary object is captured with two sensors which are each arranged in the edge region of the filter disk.
It is an object of the invention to provide a sensor apparatus, a system, a method and a motor vehicle, by means of which an occupant, in particular the driver, of the vehicle can be protected from being blinded or dazzled (hereinafter simply “blinded”) by light sources situated outside of the vehicle in a simple and reliable manner.
This object is achieved by the sensor apparatus and the method in accordance with embodiments of the invention, and by a system comprising such a sensor apparatus, and by a motor vehicle comprising such a system.
The sensor apparatus according to the invention for a system for protecting an occupant, in particular a driver, of a vehicle from being blinded by light sources situated outside of the vehicle comprises: a projection area; a shadow-casting object, said object being arranged and/or configured in such a way that at least one shadow of the object is cast onto the projection area when the object is illuminated by at least one light source situated outside of the vehicle; an image capturing device which is embodied to capture an image of the shadow of the object cast onto the projection area; and a control device which is embodied to ascertain at least one property of the at least one light source on the basis of the captured image of the shadow of the object cast onto the projection area.
The system according to the invention for protecting an occupant, in particular a driver, of a vehicle from being blinded by light sources situated outside of the vehicle comprises: a darkening apparatus which is embodied to attenuate or shadow light rays which emanate from the at least one light source situated outside of the vehicle and impinge on the occupant; and at least one sensor apparatus according to the invention, wherein the control device is embodied to control the darkening apparatus depending on the at least one ascertained property of the at least one light source.
The motor vehicle according to the invention comprises the system according to the invention. Preferably, the motor vehicle comprises at least one windowpane, in particular a windshield, a rear window and/or a side windowpane, wherein the darkening apparatus is integrated into the windowpane and the sensor apparatus is attached to the inner side of the windowpane facing the interior of the motor vehicle.
Preferably, a motor vehicle within the meaning of the invention is a land vehicle that is not permanently guided on tracks, in particular a road vehicle, for example an automobile, truck or bus. However, in principle, the sensor apparatus according to the invention may be used in all types of vehicles, such as e.g. in aircraft, watercraft and spacecraft as well.
The method according to the invention for protecting an occupant, in particular a driver, of a vehicle from being blinded by light sources situated outside of the vehicle comprises the following steps: producing at least one shadow of an object on a projection area when the object is illuminated by at least one light source situated outside of the vehicle; capturing an image of the shadow of the object cast onto the projection area; ascertaining at least one property of the at least one light source on the basis of the captured image of the shadow of the object cast onto the projection area; and attenuating or shadowing light rays which emanate from the at least one light source situated outside of the vehicle and impinge on the occupant of the vehicle, depending on the at least one ascertained property of the at least one light source.
The invention is based on the approach of providing a sensor apparatus comprising an object that casts shadows, for example one or more patterns, a projection area and an image capturing device for the purposes of determining at least one property of a light source situated outside of the vehicle. The object, the projection area and the image capturing device are arranged relative to one another in such a way and/or configured such that at least one shadow of the object is cast onto the projection area lying behind the object when the object is illuminated by a light source situated outside of the vehicle, for example by the headlamps of an oncoming vehicle, with the image capturing device being directed to said projection area in such a way that it may capture an image of the shadow of the object cast onto the projection area. Properties of the light source, such as e.g. the direction, position, size and/or intensity thereof, are ascertained in a correspondingly configured control device on the basis of the image of the shadow of the object cast onto the projection area, which image has been captured by the image capturing device. On the basis of the properties of the light source ascertained here, it is then possible to control a darkening apparatus, e.g. situated in the region of a windowpane of the vehicle, with e.g. individually actuatable darkening elements in such a way that the former attenuates or shadows light rays which emanate from the light source and impinge on the vehicle occupant. In particular, the darkening apparatus is controlled in such a way here that impingement of the light rays in the region of the eyes of the vehicle occupant is avoided or at least attenuated.
With the aid of the sensor apparatus according to the invention, it is possible to determine the properties of the glary light source situated outside of the vehicle, which are required for reliably controlling the darkening apparatus, in a simple manner. As a result of this, it is possible to protect an occupant, in particular the driver of the vehicle, from being blinded by light sources situated outside of the vehicle in a simple and reliable manner.
In principle, any type of light source comes into question for the light sources situated outside of the vehicle, which may cause blinding of the vehicle occupant. However, in many cases, the light source will be direct or indirect, i.e. reflected, solar radiation or headlamps from other vehicles.
Protecting an occupant of a vehicle from being blinded within the meaning of the invention should be understood to mean any measure by means of which blinding or dazzling of the occupant is avoided or at least reduced.
Preferably, the projection area of the sensor apparatus is a concavely or convexly curved area or a plane area. Alternatively or additionally, the projection area has a substantially homogeneous structure, i.e. no further structures, such as e.g. depressions and/or elevations, are provided in addition to the concave, convex or plane basic form of the projection area. Alternatively or additionally, the color of the projection area is preferably homogeneous. By way of example, the projection area may be uniformly white or light gray. Alternatively or additionally, the projection area is configured as a reflected light image area, on which incident light is reflected in a diffusely scattering manner. However, it is alternatively also possible for the projection area to be configured as a transmitted light image area, in which incident light is transmitted in a diffusely scattering manner. However, in principle, the projection area may have any geometry and/or may be structured or colored inhomogeneously, e.g. patterned. Preferably, a shadow-free calibration image of the projection area is recorded and stored by the image capturing device during a calibration of the sensor apparatus such that said calibration image may be taken into account before analyzing a recorded shadow image of the shadow cast by the illuminated object, for example by subtracting the calibration image from the shadow image.
In principle, any object which is able to produce a shadow on the projection area in the case of light incidence from a light source situated outside of the vehicle may be considered to be a shadow-casting object of the sensor apparatus. The object may have any form and degree of transparency. It is also possible to provide a transparent monochrome or electrochromic display as an object, by means of which static and/or time-varying shadow-casting patterns can be produced. In principle, the object may have one or more shadow-casting elements or patterns such that, as a rule, one or more shadows are cast onto the projection area in the case of illumination by a single light source. Preferably, the shadow-casting elements or patterns may be defined elements, such as e.g. points, lines and/or geometric figures, such as e.g. crosses, circles, ellipses or rectangles. Alternatively or additionally, the shadow-casting object is preferably a static, i.e. temporally unchanging, element, the form, size and/or orientation of which relative to the projection area does not change over time. Thus, if the vehicle equipped with the sensor apparatus according to the invention is moved relative to a light source situated outside of the vehicle, the shadows cast by the object onto the projection area in the process can only change on account of the relative movement between vehicle and light source.
The image capturing device is preferably one or more cameras which are embodied to record static and/or moving images.
Preferably, the control device is embodied to determine at least one direction with which the light from the at least one light source impinges on the sensor apparatus on the basis of a position of the shadow of the object on the projection area. To this end, an image analysis is initially used to determine the position of the shadow on the projection area. In this way, it is possible to determine the orientation of the light source relative to the sensor in a simple and reliable manner.
In a further preferred configuration, the control device is embodied to determine a measure for the size and/or distance of the at least one light source on the basis of the sharpness of the captured image of the shadow of the object on the projection area. Preferably, the sharpness of the shadow in the recorded image is determined first in this case, for example by determining the contrast at the edge boundaries between the shadow region and the illuminated regions on the projection area. This also allows properties of the light source which are required for reliable darkening to be determined in a simple manner.
Preferably, the control device is embodied to determine a measure for the intensity of the at least one light source on the basis of a brightness difference between a region of the captured image situated in the shadow of the object and a region of the captured image situated outside of the shadow of the object. In particular, the determined measure for the intensity is a relative measure for the intensity of the light source. The extent of the respectively required darkening of the incident light can be determined reliably and the darkening apparatus can be controlled correspondingly on the basis of the determined measure for the intensity, despite this simple method of determination.
Further, it is preferable for the control device to be embodied to deduce the presence of a plurality of light sources outside of the vehicle on the basis of a plurality of different shadows of the object cast onto the projection area in the captured image. In particular, the control device is embodied to determine a number of light sources outside of the vehicle on the basis of the different shadows of the object cast onto the projection area in the captured image. The darkening apparatus can be controlled taking into account the determined number of the glary light sources, as a result of which reliable darkening of the light rays emanating from the light sources is achieved.
Preferably, the projection area is configured as a so-called reflected light image area, which is substantially opaque to incident light and reflects the latter in a diffusely scattering manner.
Alternatively or additionally, the projection area may be partly light-transmissive, i.e. the projection area in this case is configured as a so-called transmitted light image area which is at least partly transmissive for incident light and transmits the latter in a diffusely scattering manner.
In the case of configuring the projection area as a transmitted light image area, the image capturing device, which includes a camera in particular, is arranged behind the partly light-transmissive projection area in relation to the direction in which the shadow of the object is cast onto the projection area. As a result of this, the shadow of the shadow-casting object is not influenced by a camera situated between the object and projection area.
When the projection area is configured as a reflected light image area, the image capturing device, which includes a camera in particular, is arranged in front of the projection area in relation to the direction in which the shadow of the object is cast onto the projection area. In this case, images of the projection area may be recorded with particularly high sharpness and brightness.
Preferably, the shadow-casting object is formed, at least in part, by the camera. In this case the camera records its own shadow on the projection area as an alternative or in addition to the shadow of a shadow-casting pattern or element. It is possible to dispense with a separate shadow-casting pattern in this embodiment. If the shadow of the camera is captured in addition to the shadow of a separate pattern, the properties of the light source may be determined particularly accurately therefrom.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.